From the prior art it is known to detect the position of a valve with the aid of a sensor. In general, there are two types of sensors which are used for detecting the position of the tappet, wherein both types comprise a signal transmitter and a sensor element which cooperates with the signal transmitter. The first type of sensors is defined as passive sensors, of which the signal transmitter is a purely passive element, e.g., a steel part of the tappet. The position of the steel part is detected by the sensor element, making it possible to deduce the position of the tappet.
In the case of the passive sensors, it has proven to be disadvantageous that the signal strength is relatively low by reason of the purely passive signal transmitter. This has a negative influence upon the measuring accuracy. By reason of the low signal strength, the passive sensors have a high level of sensitivity to external perturbations which can falsify the measuring result.
The second type of sensors is also defined as active sensors which have an active signal transmitter which is designed e.g., as an oscillating circuit or a permanent magnet. The signal emanating from the active signal transmitter is detected by the sensor element, whereby the position of the tappet can be determined. The signal strength of the active sensors is considerably higher than that of the passive sensors. However, the assembly outlay is also increased. Typically, the active signal transmitters are a printed circuit board, onto which tracks, which cooperate with the sensor element, are printed. The printed circuit board is mechanically coupled to the tappet and is guided in a laterally spaced-apart manner with respect to the sensor element such that the printed circuit board moves exactly perpendicularly with respect to the sensor element at a predefined spaced interval.
In the case of the active sensors known from the prior art, it has proven to be disadvantageous that the exact arrangement and orientation of the sensor element with respect to the signal transmitter is very complex in order to achieve sufficiently reliable measuring accuracy.
The object of the invention is to provide a valve comprising a sensor which is simple to produce and has a high level of measuring accuracy.